获取先前检查的单选按钮 [英] Get previously checked Radio Button

问题描述

给出一组单选按钮，例如:

<input id="B_1" type="radio" name="radioName" value="1">
<input id="B_2" type="radio" name="radioName" value="2">
<input id="B_3" type="radio" name="radioName" value="3">
<input id="B_4" type="radio" name="radioName" value="4">

当

我尝试将以下函数附加到onclick事件，但是它不起作用，因为它返回了当前选中的单选按钮，而不是之前选择的那个单选按钮:

my_func = function() {
    var checkedValue = $('input[type=radio]:checked').val();
    return alert("The previously selected was: " + checkedValue);
  };

我不知道是否有帮助，无论如何，这是完整的尝试: http://jsfiddle.net /H6h4R/

解决方案

尝试一下- http://jsfiddle. net/H6h4R/1/

$(":radio").on("mousedown", function() {
    $("p").text( $('input[type=radio]:checked').val() );
}).on("mouseup", function() {
    $('input[type=radio]').prop('checked', false);
    $(this).prop('checked', true);
});

click事件仅在以下一系列确切的事件之后触发:

• 当指针位于元素内部时，按下鼠标按钮.
• 当指针位于元素内部时，释放鼠标按钮.

Given a set of radio buttons, like:

<input id="B_1" type="radio" name="radioName" value="1">
<input id="B_2" type="radio" name="radioName" value="2">
<input id="B_3" type="radio" name="radioName" value="3">
<input id="B_4" type="radio" name="radioName" value="4">

​When one of them gets checked is it possible to know which was previously active (if there is one)?

I tried to attach the following function to the onclick event, but it doesn't work because it returns the the presently selected radio button instead of the one that was selected before:

my_func = function() {
    var checkedValue = $('input[type=radio]:checked').val();
    return alert("The previously selected was: " + checkedValue);
  };

I don't know if could be of any help, anyway here's the complete attempt: http://jsfiddle.net/H6h4R/

解决方案

Try this - http://jsfiddle.net/H6h4R/1/

$(":radio").on("mousedown", function() {
    $("p").text( $('input[type=radio]:checked').val() );
}).on("mouseup", function() {
    $('input[type=radio]').prop('checked', false);
    $(this).prop('checked', true);
});

The click event is only triggered after this exact series of events:

• The mouse button is depressed while the pointer is inside the element.
• The mouse button is released while the pointer is inside the element.

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